I've seen other people do it so it's not that weird but I have a shitty slea market acoustic guitar I made into a theremin for this extreme noise band I was in for awhile. Had two antenna stick out of the bottom and top and the guts jammed inside it superglued and duct taped to the inside body. Would put it through every pedal I owned and kick it and throw it around and hit it with pipes, would make horrible noises like it was being murdered.

It was weird because touching the strings would change the pitch and sliding up and down the neck would make weird bubbling noises. Like you play a chord and it sounds normal but there's this weird echo of bubbles and sizzles that follows it.

Oh, I have since replaced it with better songs but if you heard the Beastqueef song 'Don't wake the sleeping pig' while it was up that was that guitar in action.

It's lasted forever and taken a massive amount of punishment.

I taped a small, thin, pickup that I took off of some Japanese guitar to one of those feedback buster hole plug things for an acoustic so it can be removed and installed quickly. It sounds like a huge hollow body with raunchy pickups. It sounds great through the tube preamps from my old rogers R2R.

well not that big ideas but:

- multi output guitar each pick up having his own output, obviously thought to be used all together with different signal paths being both amps, pedal effects.
The original ''design'' had to be a pick up with each mic/magnet having his own output, for a total of six or different combinations of outs! Obviously it wasn't possible, i had no knowledge of how a pick-up would work at the time! However it would be possible winding the magnets individually.
After sometime i read in a magazine that Gibson made my idea but digitally in a digital guitar or something!

- a rough pedal that mechanical would bend the guitar string, however the tuning would have to be well low.

I think one of my best mods is a 4 string guitar that I played (in a decades old band) with a wooden mallet and a drumstick. Drumstick as slide ala SY. The guitar lasted a few weeks on the road and died - I'm pretty sure it died in Texas. I never was able to make another, at least one that sounded as good. This is one of the disadvantages of modding triftstore guitars - they break easily.

I miss that guitar.

when I was young I saw this dude play who had xmas lights under is scratch guard. it was white and kinda thin so you could see the lights flashing around under it. at the time I thought it was pretty neat but now it just seems stupid, flashy and excessive.

5 Grams of coke behind the transformer of a Mesa Boogie combo for a "friend".

Strangely the amp, me and the friend weighed a little less on the way home.